1. Field of the Invention
The invention relates to the manufacture of refractory fibers and in particular to coreless fibers.
2. Discussion of Prior Art
GB Patent Application No 8811893 describes a method of radio frequency heating which allows lengths of fine wires to be heated uniformly or with a desired temperature gradient without physical contact with the wire. GB Patent Application No 9005172 further discloses that uniformity of the heating of the wire can be improved by modulating the radio frequency source. These methods allow convenient manufacture of refractory fibers or filaments by chemical vapor deposition (CVD) on a core wire, typically tungsten. Such fibers do not have optimum properties, however, because several well known deleterious core effects impair the properties of the refractory material deposited on the core.